Many Iranians spent the weekend in the streets celebrating the re-election of their president. Hasan Rouhani pledged to keep opening Iran to the world and to push for more freedom at home.

STEVE INSKEEP, HOST:

To understand what's at stake, it helps to hear the story of one Iranian. His name is Mehdi Aminizadeh. Many years ago, he was attending college. It was the early 2000s, a time of relative openness. And the excitement of the moment inspired him to study political science.

MEHDI AMINIZADEH: I thought if we want to change our country, we should study about the other countries' experience about democracy. So I decided to go to a university and learn about democratization.

INSKEEP: He studied countries that went through democratic change in Eastern Europe and South Africa in the 1990s, and Mehdi became a student political leader in Iran. Then the clerics, who hold ultimate authority, began cracking down.

When did you come to the attention of the authorities?

AMINIZADEH: For several years, they knew me. And they knew I'm the - one of the students leaders that try to reach democracy in Iran.

INSKEEP: He says he was arrested four times. He was sent to Iran's famous Evin Prison, which has a wing for people considered national security threats. And he says he was tortured.

What was that like?

AMINIZADEH: It was very hard. I couldn't sleep for 54 hours. And it was really, really tough.

INSKEEP: How many hours did they keep you awake?

AMINIZADEH: Fifty-four hours.

INSKEEP: Fifty-four hours?

AMINIZADEH: Yes.

INSKEEP: And how did they keep you awake?

AMINIZADEH: They made me stand. And sometimes they pour very cold water on my face. They wanted to break me.

INSKEEP: Mehdi says he was convicted of organizing an illegal group. He was sentenced to prison and then let out on bail. It's common for Iran to allow prisoners back into society with a sentence still hanging over their heads.

AMINIZADEH: At that time, I have a child, and he was 2 and a half years at that time. And I decided to leave the country.

INSKEEP: He sent his wife and child by plane to Turkey. Fearing that he would be stopped at the airport, he traveled by land to western Iran, hired a smuggler and walked 17 hours across the border to join his family. We could not independently verify the details of Mehdi's story but can verify that he is now safe with his family in Berkeley, Calif., where he found a job.

He works for an organization called United4Iran which publishes the Iran Prison Atlas. It's a website collecting information about Iranians described as political prisoners. Mehdi's colleague, Reza Ghazinouri, gave us a tour through page after page of names and facts and faces.

I'm doing a search on the site right now. Siamak Namazi is a name that I know.

REZA GHAZINOURI: Yes.

INSKEEP: That's an American. And there we go, there's a picture of a smiling guy with glasses wearing a tie in the picture actually. That's a more prominent case, but we could go through and find hundreds here of people that are not known to the outside world really.

GHAZINOURI: Exactly. We have 3,000 profiles, more than 3,000 profiles of prisoners and former prisoners, 800 of them are still in prison. This is the lowest number we ever had in Iran Prison Atlas.

INSKEEP: Oh, so we've actually learned something there. The number of known political prisoners is less than it has been in the past.

GHAZINOURI: Yes.

INSKEEP: And the number has continued dropping just since we recorded this interview earlier this month. That fact is representative of President Hasan Rouhani's time in office. Iranians say they feel more political freedom, and they rewarded Rouhani with a landslide re-election on Friday, but laws and courts established by the clerical government remain in place. And as of today, the Iran Prison Atlas defines 685 people as political prisoners. It documents judges passing one harsh sentence after another.

And this man, Mogase (ph), has sentenced people to 1,151 lashes.

GHAZINOURI: Yes. And that's only the number of known sentences. There are many other sentences that we didn't know about, so those are the documented ones.

INSKEEP: The Prison Atlas gathers information from family members of prisoners and other sources in Iran. It's been supported by the Open Society Institute and other groups and was the creation of an Iranian-American, Firuzeh Mahmoudi.

FIRUZEH MAHMOUDI: We want to release the leaders and the most prominent potential leaders of the future. We also want to advocate for every single individual.

INSKEEP: She says her goal is an Iran where she can safely take her children someday, even though she's been critical of the government.

So you know they know who you are and that they don't approve.

MAHMOUDI: Well, the government actually says something kind of coy. They say anyone's welcome to come back. We can't guarantee they can leave the country, but you can always come home.

(SOUNDBITE OF MARCEL KHALIFE'S "TENTS")

INSKEEP: We've just heard some of the people behind the Iran Prison Atlas, which is based in California.